The aim of the proposed research is to conduct laboratory investigations leading to an automated periodontal pocket depth and attachment level measuring device. The design features include: automatic detection of the cementoenamel junction, constant adjustable probing force, and automatic recording of the attachment level. Although the conventional probe is widely used, the errors inherent in its use limit the accuracy and reproducibility of such measurements. The automated periodontal probe will serve to decrease errors and increase accuracy, thereby enhancing its value as a tool for the detection of periodontal disease, and for the assessment of periodontal disease activity. This Phase I research will he conducted in two steps. Efforts are directed toward building a prototype instrument which will confirm our preliminary experiments and prove the feasibility of using computerized signal processing to locate the CEJ and determine attachment level. This prototype instrument will be utilized in four in vitro models. Aluminum blocks with holes of a known depth will he used to assess accuracy, and root planed extracted teeth will he used to determine the ability of the probe to detect automatically the CEJ. Extracted teeth with and without root planing will be placed in a silicone matrix to simulate a soft tissue pocket of known depth and will be used to determine the accuracy and repeatability of attachment level measurements, as well as to determine the effect of calculus on the measurements. Once the principles of automated periodontal probing are established, future studies can finalize the electronic and mechanical design for commercialization. An immediate need is seen for the instrument in dental research; subsequent adoption by practicing dentists is likely if the device can be produced at the target price.